Process of manufacturing coffee.



No. 726,812.. PATENTED APR. 28, 1903. W. E. BAKER. l

PROCESS 0F MANUFACTURING COFFEE.

APPLIoA'rIoN rum; MAY 1a. ,1902. No MODEL.

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UNITE STATES ATENT OFFICE,

wILLIAIvr E. 'BAKIza on MINNEAPOLIS, MINNESOTA.

FRocFss oF MANUFACTURING COFFEE.

SZEJEQIFIGACEION forming part of Letters Patent No. 726,812, dated 4April 28, 1903.

Application led May 13,1902. Serial No. 107,093. (No specimens.)

To all wftont t may concern:

Be it known that I, WILLIAM E. BAKER, a citizen of the United States of America, and a resident of Minneapolis` in the county of Hennepin and State of Minnesota, have in. vented certain new and useful Improvements in Processes of Treating Coffee, of which the following is a specification.

Myinvention is designed for the production of an improved article of manufacture con*-L sisting of granulated roasted coffee having the granules of uniform size and havingr the dust, chaff, and other impurities, vincluding a portion ofthe tannic acid, removed therefrom; and the invention resides in a novel process of treating the coffee and in the improved product obtained as a result thereof.' Y Asis well known,the coffee-bean Inay propf; erly be described as substantially a lobated berry enveloped by a silver skin which eX- tends into the interior of the bean, surrounding or partially surrounding the core.

roasting and granulating the same, the outer portion of this silver skin, or that which covers the exterior of the bean, is removed yby hull- That portion ofthe sil-.

ing and winnowing. ver skin, however, which extends into the interior of the bean cannot be removed by this process, and as a result when the, coffee is roasted and ground it forms part of the final ground product, which is sold to the -trade and afterward made up into the beverage. This remaining silver skin when ground constitutes what may be termed tne chaff, which detracts from the appearance of the granulated coffee. Furthermore, it contains a large percentage of tannic acid, which is not only injurious, but is bitter, and thereby detracts from the davor or aroma of the body of the bean. `It is the purpose of'my invention to remove from the granulated coffee this In theordinary treatment of green coffee, priorto The apparatus shown in Fig. 1 is a crush- "ving andseparating device, consisting of a casing l, having a chute or hopper 2 at'its upper end, through which the coffee-beans are in troduced into the machine. Located beneath the discharge end of the chute 2 are the crushing-rolls 3 4 of any suitable or preferred conter-is adapted to be reciprocated by means ofV a pitman-rod 9, connected to the link 7 and voperated in any suitable manner. Beneath the screen 5 is a closed chamber 10, formed -by a bottom piece 11, an end piece 12,-and -fiexible webs 13 Y and 14, connected, respectively, to the `frame of the screen 5 at opposite ends and to the end piece 12 and side wall of the casing l. Into the chamber 10 leads au air-.inlet pipe 15', through which ablast of air is adapted to be forced, and from the casing 1, above the screen 5, leads an exhaust-pipe 16. The screen 5 is slightly inclined, so that the crushed coffee when delivered thereon may be caused to pass from one end thereof, as clearly shown in the drawings. Beneath the screen 5 and the chamber 10 are disposed a second pair of crushing-rolls 17 and 18, the same being similar-in construction to the rolls 3 and 4, heretofore referred to, but designed to crush the coffee passing between the same into a finer condition. These rolls are located between the parts 19 and 2O of a transverse diaphragm and have located above them a chute 2l, having two inclined walls into which the codec from the screen 5 is discharged. The purpose of said diaphragm is to prevent the passage of the air-current from the inlet-pipe 24 through the exhaust-pipe 16. Beneath the crushing-rolls 17 and 18vis located a shakingscreen 22, similar in all respects to the screen 5, heretofore referred to, and having beneath it a chamber 23, similar to the chamber 10,

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and connected with the screen 22 in a mannersimlar to that above described. Leading into the chamber 23 is an air-inlet pipe 24, and leading from the casing l above the screen 22 is an exhaust-pipe 25. The screen y22 is inclined and discharges the coffee therefrom into the chute or hopper 2G, whence it may be delivered from the machine to any suitable point.

The outer portion of the silver skin is removed and the coffee roasted in the usual way. I have found that roasting renders the body proper of the coffee-bean exceedingly brittle, while the embedded silver skins remain relatively flexible. These conditions facilitate the subsequent purification of the gran nlated coffee. The roasted beans are then delivered into the machine through the chute or hopper 2 to the crushing-rolls 3 and 4. By the latter the coeebeans are crushed or ground into a coarsely-granulated condition Vand dropped upon the screen 5, which is located directly beneath said crushing-rolls. On this screen, which is constantly being shaken or agitated by the means described, the crushed coffee is subjected to a blast of air entering the chamber lO beneath the screen 5 through the pipe l5 and discharging through the eX,- haust-pipe 16. This current or blast of air carries off with it the light particles of matter contained in the crushed coffee, consisting of the dust and the chaff, which latter is produced by the silver skin from the inside of the coffee-bean. As the operation continues the crushed or granulated coifeeis discharged from the delivery end of the screen 5 into the chute or hopper 2l and is then caused to pass between the second pair of crushing-rolls 17 and 1S. By the latter rolls the coffee is reduced toa more finely divided granulated condition, and from the' same it is delivered onto the shaking-screen 22. On thelatterscreenit is subjected to the action of a second blast of air, which enters the chamber 23 beneath the screen 22 through the pipe 24 and discharges from a point above the screen 22 through the exhaust-pipe 25. Any chaff, dust, or other light finely-divided impuritieswhich escaped the action of the blast of air passing through the screen 5 are removed by the blast of air to which the coffee is subjected on the screen 22. As a result the final product, which is discharged from the lnachine through the chute or hopper 26, is superior in many respects to ordinary ground or granulated coffee-that is to say, it presents a much better appearance, in that the granules are of regular size and do not disclose the presence of dust or chaff therein. Furthermore, as the chaff produced. by the silver skin from the interior of the beancontains a large percentage of tannic acid an important deleterious impurity has been removed and the flavor and aroma of the resulting product is radically improved.

Of course, if desired, the granulated product delivered from the machinethrough the discharge chute or hopper 26 may be further ground and pulverized.

I have shown and described two sets of crushing-rolls, shaking-screens, and means for subjecting the crushed coffee to the action of a blast of air; but it is obvious that I may increase or decrease the number of these sets of instrumentalites as may be found necessary or expedient.

l-Iaving now described my invention, what I claim as new, and desire to obtain by Letters Patent, is-

l. The process of preparing coffee for use, which consists in removing the outer skin; roasting the coffee, whereby the berryis rendered brittle while the embedded silver skins remain iiexible; crushing the roasted berry and releasing the skins, and finally separating the skins from the granules by means of an air-current.

2. The process of treating coifee, which consists essentially in first roasting the coffeebean, whereby the body of the bean is rendered brittle, while the embedded silver skin remains relatively fiexible; then breaking the roasted bean and freeing the silver skin, and iinally separating said skin from the broken body of the bean.

3. As a new article of manufacture, the roasted body ofthe coffee-bean, granulated and freed from the embedded silver skin.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

' WILLIAM E. BAKER.

Witnesses:

E. M. Bonsai., F. G. BRADBURY.

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